Generally, such dispensing devices are reusable, i.e. the content of the double cartridge or double syringe is sufficient for multiple applications while the static mixer can only be used for a single application and is then replaced. In applications of multicomponent cartridges or syringes in medicine, however, the tendency is toward single use. The advantage is that a possible contamination of the patient is prevented since an application for a single patient respectively a single treatment can be ensured.
The dispensing devices discussed above have a cartridge with a closure that has to be removed prior to their application in order to be able to attach the mixer. This applies especially also to U.S. Pat. Nos. 4,690,306; 5,301, 842; DE-A-34 20 323; EP-A2-0 319 135; and DE-A-101 32 417, all of which further comprise more or less complicated valve arrangements for preventing the outflow of materials when reused.